You don't have to use movie mode for HDR. I don't know what input device you are using but for example for my xbox one S and PS4 Pro I have it set to game mode and UHD On in the video expert settings. I honestly don't notice a huge difference either, basically HDR ups the brightness up to like 20 automatically so if your brightness is a bit high anyways I doubt you'll notice anything. and yeah, this is all on games where the HDR logo pops on, for example the PS4 dashboard is NOT hdr enabled but Last of Us remastered or Infamous Second Light have HDR but I'd never know the difference except the little HDR logo turns soon after I start up the game. I'm not even sure how to get that top bar to show up again without turning the TV on and off
For video playing its a bit more complicated, you have to get the 10 bit version streaming in native 10 bit mode. No clue how to do that in amazon video, probably if you get HDR lit it in the amazon prime app its working. For my PC hooked up, I use WinVLC and it plays 10 bit h265 videos in HDR mode no problem, but again there is no way I can tell the diff between HDR on and HDR off. Its complicated even more by the fact that the 10 bit HDR standard is completely different from Dolby Vision, which is 12 bit color but I have yet to see a single encode done with it.
QLED is definitely really close to OLED, it could be better on some panels that have very high NIT ratings compared to lower for the OLED screens. The big issue is the source demos in stores are driven off USB drives and doing full 4k UHD HDR running at max mbit streams, you will never see that quality outside maybe UHD discs. Definitely not on TV shows.
I struggle to find any 4k content, while there are a few 4k amazon TV show rips they are mostly upscaled 1080p since the visual effects for TV shows aren't rendered at 4k. PS4 Pro games don't render at 4k either, they render at 1080p and upscale via checkerboard rendering. Its all a scam!
Still looks nice though.